In NRS's case, there's 3 main possibilities:
1. They don't even know their own frame data (maybe they didn't keep track of it for whatever reason)
2. They're too ashamed to release the info (because it looks bad and amateurish)
3. Too many variables might indirectly affect frame data (like stance, crouching, hittable boxes) making it almost impossible to calculate.
I personally think it's #2. If NRS decided to release frame data on day 1, then it would've made them look extremely bad and unprofessional. Because the frame data would've made all the block infinites and jail strings visible. So at that point making it public would be like showing the world how buggy the game really is.
But the fact that they didn't know about the Jax and Raiden block infinite gives me good reason to believe they don't even have frame data or don't know how to use it.
Maybe they'll release the info after they've fixed all the problems and balanced the game. But I wouldn't get my hopes up. They already said in the past they had no intention in ever releasing frame data.